Oilless non-corrosive bearing



May 9, 1961 L. A. RUNTON ET AL 2,983,562 OILLESS NON-CORROSIVE BEARING IFiled May 1, 1958 /4 TEFL 0 /4 Heme Y W ATTOE/VE'Y United States Patent6 OILLESS NON-CORROSIVE BEARING Leslie A. Runton, Middle Haddam, andHenry C. Morton, Branford, Conn., assignors to The Russell ManufacturingCompany, Middletown, Coun., a corporation of Connecticut Filed May 1,1958, Ser. No. 732,302

1 Claim. (Cl. 308-238) This invention relates to oilless, non-corrosivebearings for heavy duty applications and more particularly to such abearing for marine use or the like where the parts are subjected to thecorrosive influence of salt water or spray.

The invention is particularly applicable to bearings for heavily loadedslow rotating mechanisms such as draw bridges, slucie gates ofhydroelectric projects, bearing supports for buckets on cranes, or thelike. Also to similar bearings in the marine field, which are subjectedto the corrosive action of salt watersuch as propeller bearings,rudders, and for the actuating mechanisms on floating man-made islandssuch as off-shore radar stations, oil rigs where bearing surfaces forelevators and other mechanical equipment are required.

All of these hearings are characterized by being exposed to the weather,having to operate without maintenance over a wide range of temperatures,and being ex' posed to the elements.

Generally speaking, the coeflicient of friction of a normal hearingwhich would be made of bronze with low friction inserts such as carbonor graphite impregnated with metal powders, would be influenced by theamount of oil and the thickness of this lubricating layer between thebearing and the rotating member. Due to erosion caused by the elements,unless constant maintenance is applied, this oil layer may disappear andthe coeflicient of friction would be considerably increased which mightresult in partial destruction of the bearing.

It is the object of this invention to provide a bearing surface whichrequires no lubrication and would therefore not need constantmaintenance, and would not destroy itself if no oil were present. Also,the coeflicient of friction is at least as low as that of presentbearings of the type described above.

Bearings of this type can not be loaded to any greater degree than thesupporting cement around them where bearing pressures in theneighborhood of 1200 pounds per square inch are in force.

In accordance with the present invention a cast stainless steel bearingsupport is made, so as to provide a recess on the bearing surface sidein which woven material is inserted to form the bearing surface througha molding process using time, temperature and pressure.

The shape of the stanless steel casting receiving the woven bearingsurface is conventional except that it will have one or more dove tailshaped slots in it which will be filled with fabric and bonded to thebearing surface during the molding operation. This prevents the moldedfabric bearing surface from slipping within the stainless steel supportcasting.

The fabric may be composed of a multi-ply weave using silicate yarns forstrength in the basic structure, and Teflon yarns for the exposedsurface.

The fabric is woven in such a way that after it is impregnated withphenolic resin and partially dried, it can be put in a suitable moldshaped according to the bearing surface against which it will operate,and compressed in such a manner that the hardness desirable for suchheavily loaded bearings is attained. The hardness is in the order of andequal to the hardness of soft cast iron. The compression ratio for sucha molding operation may be in the neighborhood of 2%:1. In other words,the fabric after impregnation will have an initial thickness of 2 /2times the final thickness.

In the manufacture of bearings for sluice gates for hydro-electricprojects, it is sometimes desirable that the bearing not only support ashaft but also act as a thrust hearing. A flange is turned on the shaftand one end of the bearing is flanged outwardly and covered with aTeflon fabric in the same manner as described for the inside bearingsurface so that the bearing then acts as a combination thrust andbearing support.

The fabric prior to molding is impregnated with a heatset, moldablebonding resin such as a phenolic resin or an epoxy resin or a melamineresin which has non-corrosive properties and is settable under heat andpressure to the hardness required.

The bonding resin may be a phenolic resin derived from the reaction ofphenol, cresol or a homologue with formaldehyde under controlledconditions or may comprise an epoxy resin. In the drying step themixture is heated to remove the solvent and the resin contentpolymerizes until a residual volatile content of 5% to 7% is attained.

The fabric may be molded under heat and pressure. The conversion of theresin into a thermoset form may be accomplished at a temperature of 300F. to 350 F. for from thirty to sixty minutes at pressures of 10 tons to100 tons, depending upon the area of the object being molded.

The features of this invention will be better undersood from thefollowing description, taken in connection with the accompanying drawingforming a part thereof in which a specific embodiment has been set forthfor purposes of illustration.

In the drawing: t

Fig. 1 is a diagrammatic view illustrating the weave of a fabricembodying the invention;

Fig. 2 is a top plan view of the fabric;

Fig. 3 is a longitudinal section through a bearing sup port and a moldcore illustrating the method of molding the bearing;

Fig. 4 is a partial transverse section taken on the line 4-4 of Fig. 3;

Fig. 5 is a broken perspective view of the molded hearing; and

Fig. 6 is a section illustrating a combination thrust bearing made inaccordance with the present invention.

Referring to the drawing more in detail the fabric is shown in Fig. 1 ascomprising upper and lower rows of filler shots 10 and '11,respectively. The filler shots 10 and 11 are bound together into a wovenfabric by two pairs of crossed binder warps 12 and 13 forming doublechains. Each double chain passes over alternate filler shots of the tworows and the pairs of chains are offset by one filler shot so as tocomprise a unitary weave in which all of the yarns are bound.

The filler shots 10 and 11 and the binders 12 and 13 are composed of aheat-resistant, non-corrosive material such as silicate fibers, i.e.,spun glass or quartz fibers.

The bearing surface is formed by multifilament tetrafiuoroethylene(Teflon) yarns 14. These yarns 14 are disposed over two filler shots 10as floats, then under the third filler shot 10 for binding the yarns 14to the fabric. Three such yarns 14 are woven in groups, mutuallydisplaced by one filler shot to form a twill appearance. Weftwise thebinders 12 and 13 are disposed between adjacent yarns 14 as illustratedin Fig. 2.

This fabric is characterized by an anti-friction surface composed ofTeflon floats bound mechanically to woven multi-ply backing of a resinbondable material. The Teflon yarns are of larger diameter than thesilicate yarns and thusform substantially the entire exposed uppersurface.

The fabric bearing is molded in situ onto the surface of a bearingsupport 20 using the bearing support as a part of the mold as shown inFigs. 3 and 4.

The bearing support 20 is formed with a flat upper surface 21 and with asemi-cylindrical bearing supporting surface 22. The peripheral wall 23extends circumferentially substantially 180 terminating in surfaces 24and is formed at its longitudinal ends with annular ribs 25 confiningthe ends of the bearing element. The surface 22 of the bearing support20 is provided with longitudinal, dove tail grooves 26 in which thebearing material is secured.

For forming the bearing, strips of resin-impregnated and dried fabricare laid in the grooves 26 and the impregnated and dried fabric of Figs.1 and 2 is disposed over the surface 22 of the bearing support with theTeflon faced side exposed on the inside. The assembly is then placedover a semi-cylindrical core 27 having a peripheral surface 28conforming to the surface of the shaft with which the bearing is to 'beused.

The support 20 and core 27 are then placed on a plate 30 on the bed 31of a forming press. The upper platen 32 of the press is then actuated tocompress the fabric under a predetermined pressure adapted to compactthe fabric to the required density. This may involve a reduction inthickness of the, order of 2 to 1 or 2 /2 to 1.

While maintaining this pressure the assembly is subjected to a curingtemperature for a time to cure the resin to the hardness desired, forexample to a hardness comparable to that of soft cast iron.

The finished bearing as shown in Fig. is suited for the various usesabove specified.

The thrust bearing illustrated in Fig. 6 is of the same type ofconstruction as of the bearing above described. In this bearing howevera shaft 35 is formed with a flange 36. The bearing comprises a metalsupport 37 carrying a molded fabric of the type above referred to havinga vertical annular portion 38 forming a bearing surface for the shaft 35and having a horizontal ring-shaped flange 39 against which the flange36 of the shaft 35 rests to constitute the thrust hearing. The bearingsupport 37 is formed with annular, dovetailed grooves 40 and 41 whichoverlie the ends of the molded fabric bearing member to lock the samesecurely in place. The molded fabric bearing member of Fig. 6 is similarin composition to the molded fabric bearing member of Fig. 5 with Teflonyarns exposed to form the bearing surfaces of the flanges 38 and 39.

Although a specific embodiment of the invention has been set forth forpurposes of illustration it is to be understood that the invention maybe applied to various uses and embodied in various forms as will beapparent to a person skilled in the art.

What is claimed is:

A molded fabric bearing for heavy duty high temperature applications,comprising a bearing supporting surface and a molded fabric carried bysaid surface to form the bearing surface, said fabric having a pluralityof layers of filler yarns composed of silicate fibers, warpwise yarnscomposed of silicate fibers, woven as chains and binding.

said filler yarns into a unitary structure, such silicate fibersconsisting of glass and quartz fibers, and additional warpwise yarnsdisposed over the surface of said structure and bound under spacedfiller yarns, said last warpwise yarns being composed oftetrafluoroethylene and con sistuting substantially the entire exposedbearing surface, said fabric being impregnated with a resin capable ofbonding with said silicate fibers, said resin being selected from thegroup consisting of phenolic resins and epoxy resins and being in thestate characteristic of having been cured under heat and pressure toform a rigid, molded structure suited for use as a bearing.

References Cited in the file of this patent UNITED STATES PATENTS1,986,686 Stolzenberg Jan. 1, 1935 2,804,886 White Sept. 3, 19572,862,283 Rasero Dec. 2., 1958 2,885,248 White May 5, 1959

